Before 2009, Coach Bus USA Inc. and City Sights LLC were competitors in the hop-on, hop-off bus tour market, in which open-topped buses shuttle tourists to New York landmarks for a fee. In March of that year, the two companies reportedly created a joint venture, Twin America, under which they divided the profits 60-40 in Coach’s favor. In the absence of any real competition, both companies increased their prices from $49 to $54, the lawsuit filed by the Department of Justice and the New York Attorney General alleges.

“The iconic double-decker Gray Line and City Sights buses are seen all over New York City but few people know they are a monopoly that has led to higher prices and less competition. Visitors to New York deserve better,” New York Attorney General Schneiderman said in a statement.

According to the attorney general’s office, roughly 2 million visitors to New York City use the double-decker buses a year, generating more than $100 million in profits.